Apparatus for controlling the tension of a magnetic tape

Claim 2

A tension control device for controlling the tension of a supplied strip at a constant level, comprising supply reel means having a strip wound thereon, a drive motor associated with said supply reel means for imposing a torque on the latter to maintain tension on the strip, constant drive means for driving said strip to move from said supply reel at a constant velocity, velocity detecting means for detecting the velocity of rotation of said supply reel means and converting the detected velocity of supply reel rotation into an electrical signal, and drive circuit means associated with said velocity detecting means for producing a current inversely proportional in magnitude to said electrical signal derived by saiD velocity detecting means, the output of said drive circuit means being electrically coupled to said motor so as to cause said motor to produce a torque inversely proportional to said velocity of rotation of said supply reel means, whereby said strip is supplied from said supply reel means at a constant tension.

Claim 3

A tension control device according to claim 1, wherein said drive circuit means includes a constant current circuit and is inserted in said charging circuit for said capacitor.

Claim 4

A tension control device according to claim 1, wherein said drive circuit means further includes a second capacitor and a second switching circuit, said second capacitor being connected in parallel with the first-named capacitor through the first-named switching circuit, said second switching circuit being inserted in the charging circuit for said second capacitor, said second capacitor being supplied with the charge of the first-named capacitor through said second switching circuit to thereby store a charge corresponding in amount to the charge of said first-named capacitor, said second capacitor being further connected with the input of said voltage-current converter circuit.

Claim 5

A tension control device according to claim 5, wherein said drive circuit means further includes a delay circuit connected with the output of said generator circuit, and a third switching circuit connected in parallel with the first-named capacitor, said third switching circuit being controlled for switching by the output of said delay circuit so as to cause the first-named capacitor to discharge later than a pulse provided by said pulse generator circuit.

Claim 6

A magnetic tape device for supplying a magnetic tape at a constant velocity and with a constant tension, comprising reel means for supplying and taking up a magnetic tape, a motor associated with at least said supply reel means to drive the latter, means disposed between said supply and take-up reel means to drive said magnetic tape to move at a constant velocity, means for detecting the velocity of rotation of said supply reel means and including a chopper disc mounted on the drive shaft of said motor, a photo-responsive element and a pulse generator circuit connected with said element, said detecting means detecting the velocity of rotation of said supply reel as pulses having different pulse intervals, a charging circuit including a switching circuit and a capacitor connected with said switching circuit for charging therethrough, said switching circuit being associated with the output of said pulse generator circuit, and a voltage-current converter circuit connected so as to receive the voltage of said capacitor in said charging circuit and convert it into a current corresponding to the level of said voltage, thereby to supply the current to said motor.

Claim 7

A magnetic tape device for supplying a magnetic tape at a constant velocity and with a constant tension, comprising reel means for supplying and taking up a magnetic tape, a motor associated with at least said supply reel means to drive the latter, means disposed between said supply and take-up reel means to drive said magnetic tape to move at a constant velocity, means for detecting the velocity of rotation of said supply reel means and including a chopper disc mounted on the drive shaft of said motor, a photo-responsive element and a pulse generator circuit connected with said element, said detecting means detecting the velocity of rotation of said supply reel as pulses having different pulse intervals, a charging circuit including a switching circuit and a capacitor connected with said switching circuit for charging therethrough, said switching circuit being associated with the output of said pulse generator circuit, and a voltage-current converter circuit connected so as to receive the voltage of said capacitor in said charging circuit and convert it into a current corresponding to the level of said voltage, thereby to supply the current to said motor.

Claim 8

A magnetic tape device according to claim 5, wherein said charging circuit further includes a second switching circuit connected in parallel with said capacitor, and said detecting means further includes a delay circuit for delaying the output signal pulse of said pulse generator circuit by a predetermined time interval, said detecting means being associated with said second switching circuit so as to apply said delayed pulse as ''''ON-OFF'''' control signal for said second switching circuit, whereby a current corresponding to the velocity of rotation of said supply reel is supplied to said motor in accordance with the pulse generated by said pulse generator circuit, whereafter said capacitor discharges to prepare for a subsequent cycle of operation.

Claim 9

A tension control device according to claim 1, wherein said velocity detecting means comprises an element for generating intermittent electrical signals in response to the rotation of said reel means, and a pulse generator circuit connected with said element, thereby generating pulse signals at pulse intervals corresponding to the velocity of rotation of said means, and said drive circuit means includes a switching circuit, a capacitor And a voltage-current converter circuit, said switching circuit being inserted in the charging circuit of said capacitor and controlled for switching by the output of said pulse generator circuit so as to charge said capacitor at time intervals corresponding to the pulse intervals, said capacitor being connected with said voltage-current converter circuit so as to apply its terminal voltage to said converter circuit for supply said motor with a current corresponding to the charge potential of said capacitor, whereby the current supplied to said motor is proportional in magnitude to the velocity of rotation of said reel means so that said strip may be supplied from said reel means at a constant tension.